1. Field of the Invention
This invention relates to the application of stucco or plaster in homes or other buildings and specifically to an expansion/control joint used to relieve stress and limit or control cracking in a stucco or plaster wall or surface caused by stucco or plaster shrinkage and thermal movement in the stucco or plaster wall or surface.
2. Background of the Prior Art
Stucco and/or plaster are typically used for both interior and exterior surfaces in home or commercial building construction. Stucco or plaster is routinely applied to a galvanized wire mesh over felt paper which has been attached to underlying plywood or other sheathing material. (See FIG. 1.) In order to relieve stress and limit or control cracking in a stucco or plaster surface, expansion/control joints are typically provided in the stucco or plaster surface every 144 square feet of stucco or plaster surface.
An expansion/control joint often used for this purpose comprises two plaster stops (that is, a first plaster stop and a second plaster stop), each generally comprising a perforated plastic strip approximately 2 inches wide with a plaster lip or edge acting to contain the stucco or plaster. The first plaster stop is typically installed approximately ¼ inch away from the second plaster stop with the back of the plaster lip of the first plaster stop facing the back of the plaster lip of the second plaster stop, leaving a gap between the back of the plaster lip of the first plaster stop and the back of the plaster lip of the second plaster stop. In order to provide a complete finish, a worker must install a backer rod into the gap and then apply a finishing layer of caulk in the gap and over the backer rod. This process, which is used by some builders to prevent leaks, is very time consuming.
This method of stucco installation has often resulted in leaking problems between adjacent stucco or plaster surfaces, thereby causing significant additional repair costs and frustration to both home owners and construction companies. In addition, the extra time and materials necessary for installation of the backer rod and finishing caulk layer can add considerably to the costs and duration of the construction.